Abstract: A display member capable of being supported on a horizontal surface in a first mode and on a hook member attached to a vertical surface in a second mode. A support for the display has a first portion joined at an angle to a longer second portion. When supported on a horizontal surface, the shorter portion is connected to the display. When supported on a hook member attached to a vertical surface, the longer portion is connected to the display.

Abstract: A list finder, for example, a telephone index, is provided in which all of the main parts can be integrally moulded of plastic mostly by simple moulds which do not require undercut moulding; the only essential non-plastic parts being a hinge pin pivotally connecting a base and a cover, and a spring. The base has two spaced apart pedestals each of which has laterally spaced upwardly facing and downwardly facing hinge pin seats, with a clear space being provided below the downwardly facing hinge pin seat so that this can be moulded by a unitary mould member which also moulds the underside of the base. The cover includes a planar portion and two downwards projections having a central web and a cylindrically curved flange, the flanges being engageable in T-shaped slots in the sheets of the index. The web member has an upwardly facing hinge pin seat, and an aperture is provided above this seat and the flanges so that these can be moulded by a unitary mould member which also forms the top of the cover.

Abstract: A three dimensional internally illuminated advertising device is sized the same as the panels forming a suspended ceiling and is used in place of one of the panels and is supported by the suspended ceiling grid network.

Abstract: A rifle having a telescopic sight has apparatus for recording the target as seen through the telescopic sight at the instant the trigger is pulled. The apparatus includes a beam splitter for directing to a camera some of the light passing through the telescopic sight. The shutter mechanism of the camera is coupled to the rifle trigger so that the camera will "shoot" the picture of the target when the trigger is pulled. The camera is of the instant-copy type so that pictures of the target can be viewed shortly after "shooting". The apparatus thus enables the ability of a rifleman to be tested without the need for firing live ammunition.

Abstract: The lightweight stock and frame construction for a firearm involves replacing a substantial portion of the side walls of the metal frame with forwardly extending portions of the side walls of the wooden or plastic stock. Specifically, the right hand and left hand sides of the stock are provided with right and left hand side wall extensions that extend forwardly from the forward end of the stock on each side thereof, and the right and left hand side walls of the frame are formed with openings conforming in shape to and adapted snugly to receive the said forwardly extending side wall extensions of the stock.

Abstract: A monolithic, rigid minnow dipper constructed of clear or transparent material (plastic in the preferred embodiment), including a handle and a scoop portion. The handle is hollow and conical, and serves to trap individual minnows so that they may be hooked to serve as live fishing bait. The scoop portion includes perforated sidewalls, an unperforated end wall and an unperforated lower portion which tapers toward a funneled trough-shaped handle having a cross-section shaped like a minnow. The trough opening of the handle serves to permit a hook to be inserted into the trapped minnow and, after the minnow is slipped backward a short distance, is wide enough to remove the hooked minnow there through. The handle is affixed to the scoop portion at such an angle that when held level it permits the minnow to swim headfirst into the handle. The handle has sufficient perforations to release water as it flows through the handle.

Abstract: Apparatus for jerking a fishline in response to a fish taking the bait on the end of the line, comprising a base, a one-piece, spring-biased wire arm having one end connected to the base, a trigger pivotally connected to the base and having a hook-shaped portion for engaging the arm such that a fishline connected to the outer end of the arm and through a hook-shaped portion of the trigger causes the trigger to release the arm in response to a fish taking the bait.

Abstract: A fisherman's leader and/or line dispenser and decoiler including an enclosed container and spool of fisherman's leader/line mounted within the container. A pair of first and second resilient pads are mounted within the container in a posture of opposing engagement and the resilient character of the pad material provides mutual self-biasing of the pads together. An aperture is provided through a portion of the container whereby a fisherman's leader/line may be threaded from the spool through the opposed resilient pads and out of the container so that a fisherman in withdrawing a length of leader/line will pull the leader/line through the resilient pads to erase coil memory during the dispensing operation.

Abstract: A toy having combined rotational motion about a horizontal axis and translational motion in a vertical direction. Two parallel discs are connected through their centers by a single axle. One end of a torsion resistant tape is attached to the axle, at a position between the two discs. A swivel system is attached to the other end of the tape, and a ring for holding the toy is attached to the swivel system. In order to operate the toy, the user's finger is placed in the ring and an up-and-down motion is initiated. The balance of the toy during operation is facilitated by the support provided to the axle along the width of the tape.

Abstract: A toy having combined rotational motion about a horizontal axis and a translational motion in a vertical direction. Three parallel discs are connected through their centers by a single axle. An inner disc is positioned between two outside discs leaving a gap on the axle between the inner disc and each of the outside discs. Opposite ends of a single string are attached to the axle at each of the gaps and the string is looped over a rotatably-mounted pulley. The pulley is held by a support member connected to a swivel system which is in turn connected to a ring. In order to operate the toy the user's finger is placed in the ring and an up-and-down motion is initiated. The balance of the toy during operation is facilitated by the use of a single string connected to the axle at two points, said string being looped over a support in a slidable manner.

Abstract: A flexible flying disc toy having a flat, flexible body of fabric material, whereby an advertising message or the like may be printed thereon, and a shape defining and retaining, flexible peripheral ring and rim integrally formed of vinyl or the like so that the disc toy may be folded or crumpled for storage, the toy assuming its original shape after storage and before use.

Abstract: A motor driven toy including a transmission mechanism having two output gears each engageable directly with a high speed transmission gear and a low speed transmission gear. One of the output gears is engaged with the high-speed transmission gear for the high-speed low-torque operation, whereas the other output gear is engaged with the low-speed transmission gear for low-speed high-torque operation. The change-over therebetween is well conducted by a tire load transmission cam having a synchronizing gear and a clutch mechanism provided between the synchronizing gear and the other output gear.

Abstract: Several types of toy vehicles are provided which automatically lean when negotiating turns. One such vehicle is a radio-controlled toy motorcycle, which carries two outriggers with supports that extend downward from the typical positions of a rider's feet. Each outrigger pivots about two independent axes, to bank the toy for negotiating turns. The outriggers are cam-operated from the same radio-controlled steering mechanism which operates the front fork of the toy to turn it. An articulated toy rider has arms which follow the handlebar motions, and legs which follow the outrigger supports--to suggest the illusion that the rider is supporting the motorcycle with his foot on turns. The radio receiver and control electronics, as well as electric motors to drive the rear wheel and the steering mechanism, are powered by dry cells advantageously mounted in the mufflers.

Abstract: An installation for the cultivation of crops on water includes a box-like floatable outer housing and an inner cultivation housing supported therewithin and forming a double-walled bottom and double-wall sidewalls therewith. A transparent plate glass roof surmounts the outer housing and is in air-tight relationship therewith. A drip plate of plate glass and having a plurality of holes extending therethrough is positioned over the cultivation housing. The bottom of the installation and the region between the double-wall sidewalls are in communications with the interior of the cultivation housing through the holes in the drip plate. A plurality of ventilation tubes are mounted in the cultivation housing and extend through the drip plate and roof for communication with the outside air. One set of ventilation tubes extends beyond the roof to an elevation higher than that of a second set of the ventilation tubes. A lower portion of each ventilation tube opens into the interior of the cultivation housing.

Abstract: The invention pertains to a gate of the type generally used in the supermarkets and similar establishments, comprising substantially the combination of at least a bracket including an electric motor driving a vertical shaft carrying a barrier consisting preferably of a U-shaped cross-bar, the said electric motor being operated through signals coming from a passage detecting system, characterized in that the free ends of the said barrier are pivotably and adjustably connected with supporting levers secured to the said vertical shaft, the axis of the said shaft being spaced from the vertical limiting plane of the passage by a distance which is at least equal to the thickness of the barrier of the gate, windows being provided in the bracket, thereby allowing a rotation of the said barrier of at least 90.degree. from a position perpendicular to the said limiting plane to a position parallel with the latter and vice versa.

Abstract: A window assembly comprises a hollow frame with a trackway mounted upon each frame side including opposed pairs of inner and outer channel tracks of dovetail shape in cross section. Opposed pairs of channel slides of dovetail shape are movably mounted in opposed tracks. A window support bracket overlies each slide and adjacent its lower end is pivotally mounted thereon. Upper and lower sashes are interposed between pairs of opposed support brackets and secured thereto. The upper and lower sashes and connected channel slides are adapted for vertical adjustments along the inner and outer tracks respectively, and the upper and lower sashes and connected support brackets are adapted for selective inward pivotal movement approximately 90.degree. to facilitate cleaning.

Abstract: A locking mechanism for sliding doors, particularly of railway freight cars, has a hasp pivotally connected to a member defining an edge of the door opening, the pivotal connection being resiliently mounted on the edge defining member so as to keep the hasp under tension when the door is locked, the other end of the hasp being removably connected to the door by a manually actuable element pivoted on the door and manually swingable by means of a movable handle from locked position, in which the hasp is held in tension by a resilient connection to the door edge defining member, to an over-center unlocking position, movement of the hasp between locking and unlocking position being accommodated by the resiliency of the mounting of the hasp pivotal connection to the relatively movable member. An improved seal latch is also provided.

Abstract: A safety door entrance includes a door mounted for swinging movement on hinges connected to a door jamb and a finger protector for continuously bridging a gap formed between the door heel and adjacent jamb as the door swings open and closed. The protector prevents a person's fingers, toes or other objects from accidentally being inserted in the gap and subject to damage when the door swings closed.

Abstract: A stationary window frame slidably mounts a pair of sash assemblies that are retained in the frame by fixed retainer bars limited to the lower half of the frame and by a pivotally suspended retainer for the upper half. The sash assemblies may be removed from the frame in their raised positions after displacement of the pivoted retainer to a release position.

Abstract: A band comprising continuous glass fibers provides intrusion resistance for a plastic door mounted between two vertical posts in an automobile. The continuous fibers of the band are disposed horizontally and may be separate from the door or form an integral part thereof.

Abstract: PCT No. PCT/US79/00322 Sec. 371 Date May 14, 1979 Sec. 102(e) Date May 14, 1979 PCT Filed May 14, 1979 WO80/02526 Nov. 27, 1980The ends (14,16) of cylindrical bushings 10) in which pins rotate bear relatively heavy loads. This can lead to a slight internal deformation of the bushing (10) which can interfere with free rotation of the pin. Such a problem is encountered, for example, with track pin bushings. A solution to this problem is to contour the ends (14,16) of the bushing (10) so that the inner diameter thereof flares (28,30) outwardly toward the bushing ends (14,16). This has not previously been accomplished via a single relatively non-critical operation. In the present invention a first end (14) of a cylindrically bored tube (10) is compressed radially inwardly sufficient to force it to a reduced internal diameter (18).

Abstract: A fixture capable of accurately manipulating a workpiece through a circular arc is provided. Various concepts useful in the formation of a cylindrical surface on the workpiece are developed. One fixture described includes a pair of opposing spherical surfaces which are restricted in degree of movement by a key extending from one surface into a slot in the opposing surface.

Abstract: A universal crankshaft pin and main bearing finishing machine having one pair of pin and main bearing arms with finishing shoes simultaneously engageable with one pair of pin and main bearings. A programmable controller and encoders automatically monitor drives which position and oscillate the arms over the width of the bearings for each pair of pin and main bearings until all required bearings of the crankshaft are finished. Adjustment and automatic programs are provided for different crankshafts which may vary in length, number of cylinders, stroke, axial location and width of bearings.

Abstract: A tool positioner has a main support defining a pair of main pivot axes and ncluding a guide. Respective main cranks have inner ends pivoted at the main pivot axes on a support and outer ends pivoted to ends of respective links whose other ends are pivoted on a tool holder. This holder has an elongated stem longitudinally displaceable in the guide and carries a tool which can pivot about the axis of the stem and about another axis perpendicular thereto. The two cranks can be displaced independently of each other for swinging of the tool holder about either of the main pivot axes or for displacing it along the axis of the stem.

Abstract: An abrading belt runs on rolls one of which is on a yoke. A cylinder of a fluid actuator is fastened to the yoke and opposite sides of a piston in the cylinder are sequentially pressurized to cause the yoke to angulate back and forth for shifting the belt between lateral limits. A fluidic logic oscillator circuit is controlled by lateral limit sensors to switch the cylinder pressures. A lead screw couples the piston to a nominally fixed threaded element and a splined shaft connects the piston to a reversible motor. A time interval is initiated when the belt changes directions and if it expires before the next lateral limit is reached a signal is developed which causes the motor to shift the piston to thereby change the rocking angle of the yoke in one direction so the lateral travel times of the belt will become equal.

Abstract: A stave assembly which cooperates with a plurality of staves to form a hot tub wall includes in a preferred embodiment a narrow stave having a projecting support for a seat, shelf, ladder or the like. The narrow stave is abutted by a pair of slats each of which have a chamfered edge for abutting adjacent staves. In other embodiments the stave assembly includes a stave with a support for a seat, step or the like embedded therein.

Abstract: A plurality of inflatable clear polyethylene tubes extending in spaced adjacent relationship longitudinally across a greenhouse at the eave level. A regulatable blower is arranged to deliver or evacuate air from a manifold which is in communication with each of the tubes. Operationally, the tubes are inflated to bear against each other and form a barrier for heat when sunlight is absent and are deflated to provide passages when sunlight is available.

Abstract: A hold-down system for a membrane (10) covering a rigid framework and having catenary cables (11 and 12) secured to the bottom edges of said membrane between bays, said system having a retainer sleeve (19) comprising spaced-apart plates (21) connected by inclined side bars (22) and a wedge-shaped keeper plate slidable therein to wedgably hold overlapping loops (11' and 12') of the end portions of two contiguous cables (11 and 12) and flexible linear means (16) detachably connecting said keeper plate to a foundation anchor (15).

Abstract: Self-supporting structures and panels of diverse shapes are disclosed in which basic assemblies of crossed rod elements are employed to achieve the desired shape. Further, the crossing points of crossed rod elements in the structure involved may include limited sliding connections which effect transfer of collapsing force to other crossing points which are pivotally joined. An improved hub structure for pivotally joining ends of the rod elements at the outer and inner apical points is also disclosed.

Abstract: In an earth anchor for use for embedding within the ground and to acquire a secure and snug retention therein, the anchor incorporates a shank portion having a helical blade affixed thereto, the blade having a linear cutting edge positioned at a lagging angle off the perpendicular or radius from the said shank portion; said shank portion may contain one or more of the helical blades spacedly arranged there along, or have a series of shank portions that are connectible axially together to form an anchor of greater length. An end cap is designed for mounting onto the upper end of an anchor, and having reinforcing rods secured thereto, and which may act as reinforcement for a concrete pile, foundation, or the like, as poured thereon, with the anchor providing a firm base for this type of constructed structure.

Abstract: A concrete structure is erected by prefabricating a plurality of comparatively massive like-constructed substantially concrete slabs each of which has an elongated rectangular opening therein and a plurality of bores extending therethrough, transporting the prefabricated concrete slabs from a fabrication location to a building location, digging a ground foundation trench at the building location, successively placing the plurality of prefabricated concrete slabs, one-by-one, in substantially vertical orientation into said trench with the respective rectangular openings of said slabs all being located below grade in said trench, passing comparatively rigid elements through the bores in adjacent ones of said slabs to align said slabs with one another and to mechanically fasten them to one another, and thereafter anchoring the slabs in place by pouring or pumping a flowable anchoring material such as wet concrete into the trench to fill the trench and to pass from one side to the other of each of said slabs thro

Abstract: A heat insulation system for an attic and the like comprises a moving fluid barrier between layers of static insulation. In the disclosed embodiment the fluid barrier comprises a plane of moving air which extends over substantially the entire surface to be insulated. A method of circulating air through the air passage of the air barrier to reduce the temperature gradient between the attic and an underlying room is also disclosed.

Abstract: A continuous process and apparatus are disclosed for forming products from thermoplastic polymeric material having three-dimentional patterns and surface textures on one or both faces that may be similar or dissimilar with or without a continuously changing profile and with or without shaped edges, such as shake shingle panels, board and batten panels, rough barn board panels, wainscoting panels, brick panels, stone panels, patterned door panels, similar structural wall panels, roofing or siding panels, ribbed soffits, fascia board, flooring reinforced with egg crate ribs, forms for pouring contoured concrete structures, and other three-dimensional pattern and surface textured plastic products which may extend in widths up to 4 feet or more and in lengths up to 20 feet or more.

Abstract: The object of this invention is to provide an elastomeric spring expansion joint-seal strip for sealing the gap between expansion members in highways, bridges and the like.The spring expansion joint-seal strip is an elongated seal strip of a substantially M-shaped cross section. The seal strip comprises an elongated web member for spanning a gap between a pair of structural slab members. The web member has flange portions extending along each longitudinal edge thereof. The flange portions support resilient grippers which are urged into sealing engagement with abutments on the slab members by spring means embedded within the elastomeric seal strip.

Abstract: A method and apparatus for applying a layer of flexible insulative material to the interior surface of a wall from which a plurality of shaft members extend inwardly. A flexible insulating material is applied to the interior surface and a plurality of the shaft members are directed through the insulating material. An elongated flexible fastener member engages a plurality of the shaft members to secure the insulative layer to the wall.

Abstract: Transparent storm sash panes are carefully measured and precut for particular window dimensions. The precut rectangular pane is positioned in a gauging slot of a storm sash fabricating apparatus in which an adjustable stop is moved into opposition with a punch unit engaging opposite edges of the pane to thereby establish the proper length of a storm sash frame side to be punched from an extrusion of aluminum or the like. The punch is operated to form an interlocking end on one frame side and simultaneously to form such end on another frame side. Two pairs of frame sides thus produced in the apparatus are placed over the marginal edges of the precut pane, the frame sides being of channel formation, and are secured rigidly at the four corners of the pane by corner end caps or connectors having recesses to interlock with punched tabs on the opposite ends of the frame members. Accuracy of size, durability and economy of manufacturing for the storm sashes are assured.

Abstract: A method of waterproofing subterranean walls which generally comprises peeling back the sod, making a perimeter trench around the wall, making a plurality of spaced apart vertical bore holes in the soil adjacent said wall, introducing a highly ionic inorganic salt solution into the bottom of said holes without contacting the side walls of said holes, and thereafter filling the bore holes and the trench with asphaltic emulsion, and finally placing the sod back over the trench.

Abstract: Method of manufacturing a filled packaging container comprising the steps of forming a bag on a mandrel, connecting a seam provided in a formed bag, forming a hole on an upper side of the bag and inserting a valve into the hole to provide an air pressure release after filling the container with a material. Two opposite edges of the valve are formed with two flexible portions made of foil. A sealing fluid is applied in the channel to provide a fluid film to connect the foil portions.

Abstract: A beverage carrier (package) handle feeder and inserter which is utilized in association with a conveyor for transporting beverage carriers from one location to another. The beverage carrier handle feeder and inserter has a pair of spaced apart cylindrically-shaped members. Each cylindrically-shaped member has a spiral groove formed therein for engaging and feeding the handles to a preselected position with respect to the beverage carriers. A support rod is located adjacent one end of the cylindrically-shaped members for supporting a plurality of handles to be engaged by and fed by the cylindrically-shaped member. Due to the specific angular relationship between the cylindrically-shaped members and the beverage carriers, and due to the design of the handles, individual handles are systematically inserted into individual beverage carriers during the feeding procedure.

Abstract: A feed roll on a forage harvester has a center support ring secured to the outer surface of the feed roll. This improves space availability inside the roll for a metal detector and improves the operating effectiveness of the metal detector.

Abstract: A throttle and brake control mechanism for a rotary lawnmower which is actuated by a single operating cable system. A centrifugal clutch interconnects the engine with the rotary blade of the lawnmower and the clutch includes an outer drum that is connected directly to the blade. On disengagement of the clutch at low throttle speeds, a brake acts to engage the clutch drum to stop free rotation of the drum and blade. The brake is released by an operating cable mechanism which interconnects a throttle operating lever mounted on the handle of the mower with the throttle on the engine. Movement of the operating lever from the idle position toward the full throttle position will initially release the brake from engagement with the clutch drum, and thereafter will operate the throttle to increase the engine speed, enabling the clutch to move to the engaged position to cause rotation of the blade.

Abstract: An attachment for the lower end of a vertical drive-shaft of a wheel-mounted power mower of the rotary lawn mower type comprises a balanced assembly of centrally-bored shaft-engaging hub together with a plurality of equi-distantly spaced radially extending arms each of which carries a boss or lateral enlargement adjacent its outer end for receiving a quickly and easily replaceable flexible cutting line which projects freely therefrom in the general direction of the arm by which it is carried. The lower end of the vertical drive-shaft of the prime mover of the rotary mower, which ordinarily receives the mid-section of a rigid metallic cutting blade that is sharpened adjacent each of its ends, is attached to the hub of the rotary assembly of the invention, suitable adapter means being provided for accommodating driveshafts of different sizes.

Abstract: An improved lawnmower blade for cutting in a substantially horizontal position, of the type including a strip of metal having a substantially flat central region and end portions provided with cutting edges on opposite sides of the blade, the cutting edges being at a level lower than the central region in the position of operation and extending substantially parallel to the surface thereof and being joined by transitional zones to the surface of the central region; these transitional zones extend at the ends of the blade, from the cutting edges to the trailing edges of the blade respectively and which are progressively shorter with increasing distance from the ends. The improvement provides a hump formed in the blade, associated with each transitional zone, for aiding in the ejection of grass from a lawnmower. Each hump merges with its associated transitional zone and is directed towards its associated trailing edge. Advantageously, each hump has an open mouth directed towards its associated trailing edge.

Abstract: A knife assembly for mounting in a combine header for cooperation with the radial feed fingers of the central drum portion of a rotary auger in which a plurality of transversely spaced knife bars fixed to a knife frame are pivotally supported upon a mounting frame fixed in relation to the feed opening of the combine header, so that the cutting edges of the knife bars are closely spaced to the central drum portion of the auger and interdigitate with the radial feed fingers of the auger drum portion, in order to cut exceptionally long vegetation, such as stalks or vines, carried by the auger before such vegetation reaches the feed opening to the combine.The knife assembly further includes adjustable stop means for accurately locating the cutting edges of the knife bars close to the central drum portion of the auger, and a locking means for locking the knife bars in an elevated inoperative position to permit cleaning out the cut vegetation in the central drum portion of the auger.

Abstract: A decorative composite non-plied frieze yarn for use in embroidering, sewing and the like. The composite yarn includes a core formed from a single plied frieze yarn having a spiral wrap of a decorative metallic yarn applied in a first rotational direction thereto and subsequently a non-metallic cover yarn spirally applied thereover in a second opposite direction. The single ply frieze core yarn itself includes a non-metallic core strand about which a first metallic strand is spirally wrapped in a first direction and subsequently about which a non-metallic cover yarn is wrapped in a second opposite rotational direction. Accordingly, the present composite frieze yarn includes three non-metallic strands and two metallic strands.

Abstract: Each wire of bare stranded electrical conductor and wire rope when supported outdoors is constantly sliding and rubbing against each adjacent wire in the stranded article due to temperature changes and wind induced vibrations. If the articles are made non-specular or dulled by abrasive blasting the completely stranded article, abrasive particles are entrapped on the interior wires and may cause premature wear and failure of the article. Articles are made non-specular or dulled without abrasive blasting by electrostatic cloud fogging or other methods that only affect the visible surface of the outer wires in the completely stranded article. Overhead supported stranded articles are made non-specular or dulled to reduce visibility because of public demand.

Abstract: The ducting extending a substantial axial length of a gas turbine engine is faired to transition the annular flows of the core engine and fan to a rectangular separate flow in a pair of two-dimensional exhaust nozzles so as to control each flow individually. Each flow is judiciously located to achieve noise control and infrared suppression.

Abstract: A diesel particulate trapping and incineration system including a porous wall monolithic ceramic filter element having dual open-ended inlet passages separated from adjacent exhaust passages by particulate filtering porous walls. A balancing system for the distribution and incineration of particulates is provided including dual inlet ducts feeding exhaust gases to both ends of the inlet passages and valve means for controlling the amount of inlet gas flow entering the open opposite ends of the inlet ducts. In this way control is obtained of distribution of particulates over the length of the inlet duct walls as well as of the incineration of particulates upon heating of the exhaust gases to incineration temperature.

Abstract: Stirling cycle apparatus including a compressor or expander for cyclically compressing or expanding a working gas, a displacer for cyclically displacing the working gas, a rotatable shaft, and a drive mechanism for coupling the compressor or expander and the displacer to the shaft, the drive mechanism being such that the relative timing of their operating cycles can be altered. Additionally a low vibration compressor or expander is provided.

Abstract: A tandem master cylinder device having a cylinder body slidably receiving therein a driving piston and a floating piston so as to define a first liquid chamber and a second liquid chamber, the device housing a liquid pressure control valve by which a differential in output liquid pressure between a front brake pressure and a rear brake pressure is produced. A stepped piston is mounted on the floating piston to open and close a poppet valve.